Cochlear implants are used to provide individuals suffering from sensorineural hearing loss with the ability to perceive sound. Cochlear implant electrically stimulates the auditory nerve via an electrode array implanted in the cochlea to induce a hearing percept in the prosthesis recipient. Acoustic hearing aids are used by individuals suffering from conductive hearing loss occurring when normal mechanical pathways conducting sound to hair cells or the hair cells in the cochlea are impeded.
Generally, a listening device, such as a hearing aid or the like, includes a microphone assembly, an amplifier and a transducer assembly. The microphone assembly receives acoustic pressure waves, and generates an electronic signal representative of these sound waves. The amplified and possibly modified (processed) electronic signal is communicated to the transducer assembly. The transducer assembly, in turn, converts the processed electronic signal into acoustic energy for transmission to a user. Other types of hearing aids use implantable electrode devices that directly stimulate the nerves. Yet another type of listening devices includes bone conduction speakers to transmit the converted vibrations to the cochlea. Other versions of such devices are based on vibration of one or more of the auditory ossicles.
Lately, some devices have been described of the type that directly vibrate the promontorium or even the fluid inside the cochlea. Devices utilizing direct vibration of the promontorium include an electromagnetic vibrator that is attached to the bone, while devices utilizing direct vibration of the fluid inside the cochlea require drilling of a hole in the promontorium. Such techniques are described for example in U.S. Pat. No. 7,618,450. This patent discloses an implantable hearing system comprising a vibration actuator and an implantable device to be used as an artificial fenestrum implantable in a bony wall of an inner ear. The device comprises a frame made of a bio-compatible material and provided to be applied at least partially in said bony wall, the frame being provided with a wall part formed by a membrane forming a barrier with a perilymph of said inner ear when applied in said bony wall. The membrane is provided to form together with the frame an interface with the inner ear, said interface being provided for energy transfer towards and from said inner ear, while the membrane is electrically dissociated from the vibration actuator and provided for receiving vibration energy therefrom.